Surfboard having some of the above features are already known in the art.
For instance, surfboards which are lightweight can be made from expanded synthetic-resin foam covered with a tough skin of synthetic resin. Also falling into this class are surfboards made of solid balsa which is carved to shape. However, neither the foam or balsa types have high flexibility, or any significant bending flexibility for that matter. Hollow surfboards are also known and are usually made of woods other than balsa, as well as of balsa with the grain parallel to the broad surfaces. They have advantages in that they are also lightweight and have limited flexibility because of their hollow interiors.
It has been found in the surfing art that high flexibility in a surfboard increases the maneuverability of that board so that higher flexibility, buoyancy, and dimensional stability must be combined for greatest control, maximum speed and most effective performance in surfing for pleasure or in competition.